An attachment device is described in German Patent No. DE 31 49 310. This reference describes the attachment of electrical installation appliances on profiled hat rails, for which purpose slides are provided which are guided in the housing of the installation appliance and are pressed resiliently inward are provided. The inwardly facing ends of these slides are each provided with a lug which engages behind the profiled hat rail. The hat rail is arranged in a free standing position, so that even relatively high appliances can be attached to the hat rail.
German Patent No. DE 91 10 337 U1 describes an attachment device having a snap-action device for snapping onto a hat rail. Screw eyelets for attachment to a plate are provided on a housing base. On the underside of the housing base, the snap-action device has a latching lug with a beveled area which attaches to the hat rail.